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In our legal system, judges are called on to make tough decisions all the time. You'd expect that these decisions would be fair and unbiased, and not influenced by extraneous factors. And that's why I was surprised after I read a scientific paper actually called Extraneous Factors In Judicial Decisions. "Extraneous Factors"?!

This paper claimed that in their study of parole, a judge's decisions depended mostly on how much time had passed since the judge last took a break. I find that totally astonishing.

One thing I learned as a medical doctor is that making decisions can be very hard. Both military and medical people have to make far-reaching decisions — and often without enough information. It is well-known that even if you do possess enough information, having to repeatedly make decisions or judgements will deplete your brain's executive function and mental resources — in plain English, you get exhausted.

This study specifically looked only at prisoners who were applying for parole. Parole is the early release under supervision. The sample size was large enough to do good statistics with.

There were eight Jewish-Israeli judges (six male, two female) with an average experience of 22 years. Over a 10-month period, they made 1112 parole rulings over 50 sitting days and were responsible for about 40 per cent of all the parole rulings in the state of Israel.

The prisoners were about two-thirds Jewish-Israeli males, one-third were Arab-Israeli males — with only a small percentage of rulings made for female prisoners. The crimes that the prisoners committed included embezzlement, assault, theft, murder and rape.

There are many factors that could influence a judge's decision. These include the number of previous incarcerations of the prisoner, the gravity of the crime committed, the time already served in prison, the availability of a rehabilitation program in the location to which the prisoner would be released, and the age, gender, religion and nationality of the prisoner.

Most of these factors didn't affect the judge. The two factors that had a little bit of influence on the judges' decisions were the number of previous incarcerations and the availability of rehabilitation program.

But overwhelmingly and incredibly, the most powerful and significant factor affecting which prisoners were granted parole and which were sent back to prison was simply the length of time that the judge had spent judging since their last meal break. I find this absolutely amazing.

The judges had two meal breaks each day. So they had three separate sessions each day, separated by their 20-minute morning snack and a 60-minute lunch.

First thing each morning, the judges would grant parole to about 65 per cent of the prisoners applying for it. As the morning wore on, this would zig-zag relentlessly downward to zero. Then they would have their morning snack.

After the morning break, the judges would again grant parole to 65 per cent of the applicants. This would then bumpily drop down to around 10 per cent. Then they would have lunch.

After lunch, the judges would again grant parole to 65 per cent of the applicants. This would then plummet quickly to around 10 per cent, bounce around this level as the afternoon wore on, and then drop to zero. Then they would go home.

Astonishingly, nobody involved in the parole system had any idea that this was happening: not the prisoners' attorneys, not the criminologists and social workers on the parole board, and not the judges.

The authors of the paper summarise this with: "We find that the percentage of favorable rulings drops gradually from around 65 per cent to nearly zero within each decision session and returns abruptly to around 65 per cent after a break."

They also say: "Our findings suggest that judicial rulings can be swayed by extraneous variables that should have no bearing on legal decisions."

Perhaps the word "suggest" is a little mild. Perhaps the judges were running out of will-power as the time increased since their last break and so were taking the "easy" option of not changing anything (by refusing parole).

So, if you or a relative or friend should end up in court before a judge, it might be worthwhile getting friendly with the court official who is in charge of schedules. Or perhaps you could bring some cupcakes for the judge…

Comments (6)

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Padre :

12 Sep 2012 7:36:03am

Read the book "Thinking, fast and slow" by Daniel Kahneman (who edited said paper). Amazing insight into the way we make decisions and interpret the world from one of the fathers of behavioural economics (although he is really a psychologist).

alban :

Ben of BNE :

13 Sep 2012 10:08:02am

From reading only this article I can't see the rekation to food. If anything the food factor would be the opposite as our bodies use energy to digest food - causing tiredness immediately after a meal - before the energy is released some time later giving us more oomph!

I would think this affect was due to emotional fatigue as each case grinds down the judge's tolerance.